EDMONTON — New research suggests industry and government are badly underestimating Alberta's emissions of one of the most potent greenhouse gases.

The difference between official estimates and the measured results suggests the province's energy industry could have to double its planned methane emission cuts if Alberta is to meet its promised 45 per cent reduction.

"A lot of eyes are going to be really wide when they see the comparison," said Carleton University's Matt Johnson, author of the study published in Environmental Science and Technology. "If we thought it was bad, it's worse."

A spokeswoman for the Canadian Association of Petroleum Producers said industry believes it will reach reduction targets.

"We are confident that we will achieve the new methane reduction targets through development and implementation of existing and new technologies and operating practices, and the continued development of effective policies," Chelsie Klassen said in an email.

Currently, industry is only required to report how much methane is released during flaring and venting. So-called fugitive emissions from equipment such as leaky valves have only been estimated.

Johnson's study is the first to use aerial flyovers of oil and gas fields to actually measure released methane, a greenhouse gas about 30 times more powerful than carbon dioxide.

The planes made seven passes over a region of conventional oil and gas around Red Deer in central Alberta and four passes over the heavy oil centre of Lloydminster. The surveys were done over 10 days last fall.

The planes flew over thousands of wells in both areas to reduce the odds that results were distorted by unusually high releases from a few sites, said Johnson.

Researchers were able to distinguish between industrial and agricultural methane emissions by tracking trace amounts of ethane — a gas released by oil and gas wells, but not by cattle.

"That allows us to attribute it," Johnson said.

The total measurements were compared with methane releases reported by industry and methane emissions estimated in the most recent National Pollutant Release Inventory.

In Lloydminster, results from the airborne tests found the type of heavy oil recovery used in that area released 3.6 times more methane than previously thought.

That same heavy oil technique is widely used elsewhere in Alberta, including the Peace River, Cold Lake and Athabasca regions.

If methane emissions from those other regions are equally underreported, Johnson said, Alberta could be underestimating releases of the gas by as much as 50 per cent.

"To achieve the kind of reductions that both the province and the federal government are trying to get, they're going to have to focus on those sites," he said.

In Red Deer, Johnson's measured results were roughly equal to the total of reported releases and estimates of fugitive releases.

But the study confirmed that fugitive emissions — which are currently unregulated — account for 94 per cent of released methane. That has major implications as governments consider new regulations on the gas, said Johnson.

"You can't ignore those sources. Those leaks really are a big deal."

Klassen said the study's methods still aren't fully reliable.

"Airborne measurement technology is relatively new and comes with uncertainties that need to be validated," she said.

"This study is useful as a reference point among widespread efforts to estimate methane emissions."

Johnson said the study suggests a need for tougher and more expensive inspections and detection equipment for conventional oil and gas producers.

"Some in industry are not going to like that because there's costs involved. But this study reveals those sources to be really important."

Ottawa and Alberta have pledged to reduce methane emissions by 45 per cent or 2012 levels by 2025. The province has already committed $40 million from its carbon tax to help cut 500,000 tonnes of methane.

Industry has so far been generally supportive of methane cuts. Less methane released to the atmosphere means more saleable natural gas in the pipeline.

Ottawa estimates compliance costs for draft regulations released last spring to be $3.3 billion over 18 years, partially offset by recovered methane worth $1.6 billion.